The first thing to know is that
part of your natural tiredness comes from a molecule called
adenosine, which is produced by your body while it chugs along
through the day. "While you sleep, the concentration of adenosine
declines, gradually promoting wakefulness," the video explains.
Meanwhile, the more adenosine that builds up, the sleepier you
feel.

Your morning coffee is able to hijack that process because
caffeine looks a lot like adenosine to your brain cells:

Because of its similar shape, caffeine can bind to the adenosine
receptors in your brain. Once the caffeine is locked into
adenosine's rightful spot though, there is no way for the
adenosine to stick around — which prevents it from building up
and making you sleepy.

Without the molecule that usually induces exhaustion, "our
natural stimulants run wild," Joseph Stromberg writes in Smithsonian. The result? You feel wide awake
— at least for a while.

But all good things must come to an end, and your brain quickly
wises up to your tricks.

When the adenosine is continually blocked from binding to its
receptors, your body eventually creates more receptors —
which means you need even more caffeine to plug them up. This can
make kicking your coffee habit increasingly difficult, and make
you need more and more caffeine to stay alert.

"When you try to quit drinking coffee or miss your daily intake,"
Moffit and Brown explain, "you might experience some withdrawal
symptoms and feel more tired than you would have before you ever
drank coffee."

But caffeine does more than just block adenosine. It can also
pump up your levels of adrenaline and boost your mood — "the
exact same thing cocaine does, just to a lesser degree," the
video says.